Field
The present technique relates to a measurement circuit and method for generating an oscillating output signal used to derive timing information.
Description of the Prior Art
There are many situations where it is useful to be able to determine timing information in relation to certain circuit blocks used within data processing systems. Often such circuit blocks will include a sequential storage element, for example a flip-flop. The circuit block may in some instances be the sequential storage element itself, or alternatively may comprise the sequential storage element along with some associated circuitry, such as some combinatorial logic circuits used to process the output of the sequential storage element.
For example, when designing a standard cell library, a standard cell representing a flip-flop may be designed, and it is often useful to determine certain timing information in relation to the flip-flop, for example the clock-to-Q delay of the flip-flop. As another example situation where it is useful to derive timing information for a circuit block, an integrated circuit will typically include one or more critical path circuit blocks, where a signal output from a sequential storage element may then be processed through some combinatorial logic circuits in the critical path prior to the output then being stored in a subsequent sequential storage element. It is often useful to be able to measure the time taken to process signals through such a critical path, as this can affect certain operating parameters, such as the operating frequency at which the integrated circuit can be run.
It would be desirable to provide improved techniques for deriving timing information of circuit blocks such as those discussed above.